As long as Simon Bridges keeps "twisting" the truth of what's in the Tax Working Group (TWG) report, Sir Michael Cullen will keep getting paid, a Labour MP has said.
The TWG released its report on February 21, but chair Sir Michael will keep getting paid $1062 for every full six-hour day of work he does up until the end of June.
Labour MP Kris Faafoi told The AM Show on Friday it's now his job to correct the record whenever the National Party leader spouts "very inaccurate" claims about what's in the report.
"Because [Mr Bridges] is going out and - I'll try and be diplomatic - misconstruing what is in the report and putting a whole lot of inaccurate hypotheticals out there that I think need to be dealt with.
"It is their report, and I think he has an issue with the way that it's being twisted, and is putting things right."
Among Mr Bridges' claims Sir Michael has responded to publicly are that average New Zealanders' KiwiSaver accounts would be worse off by about $64,000 over their lifetime, under the TWG's capital gains tax proposal.
Sir Michael called this claim "hysterical", and said other recommendations, if adopted, would more than offset any KiwiSaver losses for most people.
"I think he's allowed to defend his report Simon is... twisting in a very inaccurate way," said Mr Faafoi.
Sir Michael told RNZ he wouldn't be costing the taxpayer as much as National might think. He only billed for two days' work in February, and expects to bill for the same in March.
National MP Judith Collins, appearing on The AM Show alongside Mr Faafoi, said it was "not okay" for Sir Michael to be "engaging in political debate and being paid to do so, when he's apparently now not a politician".
She also lashed out at the former Finance Minister's qualifications.
"He's not a tax expert. He never has been."
As Finance Minister between 2000 and 2008, Sir Michael ran eight consecutive Budget surpluses.
Ms Collins said if Sir Michael was getting paid, so should Robin Oliver, a member of the TWG who disagreed with its overall recommendation of a capital gains tax.
"He can defend it all he likes - just don't get paid for it. What's going on here? What about Robin Oliver, who wrote the minority report? He actually is a tax expert. You're not paying him to go out there and say what he wants to say. It's not good enough."
Bob Buckle, who chaired the National Party's Tax Working Group in 2010, didn't get paid at all.
"I wasn't paid anything extra to do this. This was something I agreed to do," he told RNZ.